The researchers found that there was a correlation for lower cardiac index with lower resting CBF in the left and right temporal lobes. When participants with prevalent CVD and atrial fibrillation were excluded, the results were similar. There was no correlation for cardiac index with CBF in other regions or with CVR in all regions. In secondary cardiac index × cognitive diagnosis interaction models, only in cognitively normal participants were cardiac index and CBF associations present, and these affected a majority of regions assessed, with strongest effects in the left and right temporal lobes.

"Among older adults without stroke, dementia, or heart failure, systemic blood flow correlates with cerebral CBF in the temporal lobe, independently of prevalent CVD, but not CVR," the authors write.